FIELD OF THE INVENTION
The invention relates to a fuse bank.
Fuse banks are parts of integrated circuits. A fuse bank disposed above a substrate of an integrated circuit has a fuse link that is isolated from the integrated circuit. Fuse links (also known as "fuses" for short) are parts of electrically conductive regions that can be severed or destroyed mechanically or thermally, for instance. As is well known, by selectively severing the fuse links of an integrated circuit toward the end of their production process, a configuration of the integrated circuit can be accomplished. Severing or breaking the fuse links, which is typically carried out through the use of a laser, destroys a protective layer above the integrated circuit in the region of the fuse links, and it is possible for charged particles (ions) to penetrate the substrate located beneath the fuse links. In order to prevent the ions from migrating through the substrate, so-called "guard rings", which enclose a region around the fuse link, are often provided. The guard rings around the fuse links are disposed under the fuse links in the substrate and by way of example can be provided in the form of diffusions.
Such guard rings perform a so-called "getter function", that is they catch ions. To that end, they are each connected to one supply potential of the integrated circuit.
If a guard ring, which of course represents a first doped region, is adjacent a second doped region of the same conduction type, and if that second doped region is connected to a different supply potential from that of the first doped region, then a breakdown of a parasitic field effect transistor formed by the two doped regions and an intervening insulation can occur in the event of ESD (electrostatic discharge). In order to prevent a destructive breakdown of the parasitic transistor, the spacing between the two doped regions can be increased, so that the breakdown voltage increases as well. However, that requires additional layout area.